Intercalators are a group of compounds that bind between the DNA base pairs. This intercalation can produce an interruption of transcription, replication and/or topoisomerase activity. It has been found that many compounds that bind to DNA by intercalation have antiproliferative properties and in vivo antitumour effects. Intercalators have been used as anticancer drugs. Cryptolepine is a naturally occurring alkaloid and it is used in traditional medicine against malaria. Its formula, shown below, is structurally close to some compounds of the present invention. Cryptolepine is able to bind CG-rich sequences of DNA containing non-alternating CC sites, and it has been reported as potential anticancer drug (cf. e.g. J. N. Lisgarten et al., “The antimalarial and cytotoxic drug cryptolepine intercalates into DNA at cytosine-cytosine sites”, Nature Structural Biology 2002, vol. 9, pp. 57-60). Thus, the provision of new intercalators with anticancer activity is highly desirable.
